Is the 260/230 nm absorbance ratio specified for RNA derived from the PAXgene Bone Marrow RNA System?
No. The 260/230 nm absorbance ratio is not specified for the PAXgene Bone Marrow RNA extraction kit. In contrast to a reduced 260/280 ratio, which results from a protein contamination of the eluted RNA and can lead to inhibitory effects in down stream applications, there is no negative impact of a reduced 260/230 ratio on any down stream application reported to date and therefore it is not necessary to specify this.
In addition, because the elution buffer contains very low concentrations of salt that absorb at wavelengths between 220 and 230 nm, it is necessary to zero the photometer properly. Do this by preparing a solution for zeroing the photometer which contains a similar salt concentration as the sample to be measured by using the same volumes. Add the same volume of Buffer BMR5 as the volume of RNA sample to be diluted into a fresh volume of the buffer in which you will measure the absorption (we recommend 10 mM Tris Cl pH 7.5 buffer for this purpose).